Children are now being born dead and malformed in numbers not seen since then, claim the advertisements placed by a British charity, the Bhopal Medical Appeal.

The advertisements show pictures of severely malformed or brain damaged children and the text says: “Some injuries are too harrowing to show, like the eye engulfed by a raw tumour that left a small girl in agony until it finally killed her.”

The charity, which funds two clinics in Bhopal, has also funded a “huge, rigorous study covering more than 100,000 people exposed to gas, to poisoned water, and to both.

“The work is almost finished. Results have to be confirmed and analysed but indications are that many families have been poisoned twice, first by Carbide’s gases, then by contaminated water.

“In poisoned areas birth defects are occurring at rates many times the Indian average.”

The advertisements say that after the gas leak, the Union Carbide plant was abandoned with the lethal pesticides still inside, while nearby were lakes of toxic waste, despite fears that local water supplies would be affected.

As early as 1999, a Greenpeace study found many wells contaminated with heavy metals and chemicals. The same contaminants were in the blood and breast milk of women living downstream from the factory.

In 2006 doctors visiting the affected areas found almost half the children they examined were brain damaged. Since then, the charity says, the situation has worsened.

The damaged children get no government help, it claims, and “Union Carbide and its owner Dow Chemical say the dumped wastes, poisoned water and human pain are nothing to do with them.”

Union Carbide says it has “worked diligently to provide immediate and continuing aid to the victims and set up a process to resolve their claims – all of which were settled 21 years ago.”

It adds that in 1998 the Madhya Pradesh state government took full responsibility for the site. The state government maintains it has gone to great lengths to organize “systematic relief and rehabilitation in the disaster area.”